Modification method, method for manufacturing resin article having plating layer, and resin article having plating layer

ABSTRACT

There is provided with a modification method. Ultraviolet rays are irradiated on part of a surface of a resin article, so as to selectively modify the part of the surface of the resin article such that an electroless plating layer will be deposited. The ultraviolet rays are irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a modification method, a method for manufacturing resin article having a plating layer, and a resin article having a plating layer.

2. Description of the Related Art

A resin article having a plating layer that has a predetermined pattern formed on the resin article is useful as a circuit board or a conductive film or the like. Also, the uses of a resin article having a plating layer are not limited to these; for example, a resin article having a plating layer of zinc oxide or the like can be used as a functional film such as a UV-cutting material or a photocatalyst.

Consequently, methods for providing a plating layer having a predetermined pattern on a resin article have been investigated. For example, Japanese Patent Laid-Open No. 2008-094923 describes a method for manufacturing a printed circuit board using surface modification by ultraviolet rays. Specifically, first, an ultraviolet ray lamp is irradiated on an entire surface of a cyclo-olefin polymer material, to perform surface modification necessary for electroless plating. Then, a plating layer is formed by performing electroless plating on the entire modified surface of the cyclo-olefin polymer material, and the result is used as material of a printed circuit board. By using a photolithography step and an etching step to process the obtained plating layer so as to have a predetermined pattern, it is possible to provide a plating layer having a predetermined pattern on the cyclo-olefin polymer material.

Technology is also known in which conductive line having a predetermined pattern is formed by irradiating ultraviolet rays according to a predetermined pattern on a resin article. For example, Japanese Patent Laid-Open No. 7-192790 describes irradiating ultraviolet rays on a conductive polymer through a mask that has an ultraviolet ray shielding portion according to a predetermined pattern. The conductive polymer degenerates and becomes insulated in portions where the ultraviolet rays have been irradiated, and portions where the ultraviolet rays were not irradiated due to being shielded by the ultraviolet ray shielding portion function as conductive line.

SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a modification method comprises: irradiating ultraviolet rays on part of a surface of a resin article, so as to selectively modify the part of the surface of the resin article such that an electroless plating layer will be deposited, wherein the ultraviolet rays are irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article.

According to another embodiment of the present invention, a modification method comprises: irradiating ultraviolet rays on part of a surface of a resin article through a shielding member having a UV-transmissive portion so as to selectively modify the part of the surface of the resin article such that an electroless plating layer is deposited, wherein the shielding member condenses ultraviolet rays which go through the shielding member.

According to still another embodiment of the present invention, a method for manufacturing a resin article having a plating layer comprises: selectively modifying part of a surface of a resin article by irradiating ultraviolet rays on the part of the surface of the resin article, the ultraviolet rays being irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article; and forming a plating layer on the part of the surface of the resin article by electroless plating.

According to yet another embodiment of the present invention, a resin article having a plating layer is manufactured according to a method comprising: selectively modifying part of a surface of a resin article by irradiating ultraviolet rays on the part of the surface of the resin article, the ultraviolet rays being irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article; and forming a plating layer on the part of the surface of the resin article by electroless plating.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a method for irradiating ultraviolet rays according to one embodiment.

FIG. 2 is a flowchart of treatment according to one embodiment.

FIG. 3 shows ultraviolet ray irradiation through a single slit.

FIG. 4 shows ultraviolet ray irradiation through two slits.

FIG. 5 shows ultraviolet ray irradiation through a diffraction grating.

FIGS. 6A to 6C illustrate a method for manufacturing a resin article having a plating layer according to one embodiment.

FIG. 7 shows a resin article having a plating layer obtained in Example 1.

DESCRIPTION OF THE EMBODIMENTS

When manufacturing a printed circuit board with the method described in Japanese Patent Laid-Open No. 2008-094923, a photolithography step and an etching step are necessary. Therefore, there are the problems that cost increases, and a large amount of waste liquid is produced so the environmental burden is high. On the other hand, the method described in Japanese Patent Laid-Open No. 7-192790 is only applicable to a special conductive polymer.

According to an embodiment of the present invention, a fine plating pattern can easily be formed on a resin article.

The inventors of the present application investigated modifying part of a resin article such that electroless plating is deposited by irradiating ultraviolet rays on only a portion where a plating layer is intended to be provided, in order to provide a plating layer having a predetermined pattern on the resin article. First, ultraviolet rays were irradiated on the resin article through a photomask where a UV-transmissive portion has been provided according to the predetermined pattern. When electroless plating was performed on the resin article after irradiation, it was confirmed that a plating layer was deposited in the portion where ultraviolet rays were irradiated. However, when a photomask having a fine UV-transmissive portion, for example an opening with a width of 5 μm, was used in order to provide a plating layer having a fine pattern, it was discovered that despite performing electroless plating, a complete plating layer with a width of 5 μm was not deposited, and disconnections occurred in some places.

The inventors of the present application presume that the reason for this is as follows. First, it is conceivable that when the UV-transmissive portion is fine, light scatters and is attenuated due to the operation of light diffraction, so the resin article cannot be sufficiently modified. Second, it is conceivable that the amount of ozone generated becomes small. When ultraviolet rays are irradiated in oxygen, ozone is generated in the vicinity of the resin article, and it is conceivable that the generated ozone promotes modification of the surface of the resin article. However, when the UV-transmissive portion is fine, the contact volume of ultraviolet rays and ozone decreases, so it is conceivable that the amount of ozone generated becomes small.

After carrying out various investigations in consideration of these problems, the inventors of the present application discovered that a resin article can be modified according to a fine pattern by irradiating the surface of the resin article with ultraviolet rays through a shielding member described below.

Following is a description of embodiments in which the present invention is applicable, with reference to drawings. However, the scope of the present invention is not limited by the below embodiments.

According to the modification method of the present embodiment, part of the surface of a resin article is selectively modified such that electroless plating is deposited. Specifically, the modification method according to the present embodiment includes a modifying step of irradiating ultraviolet rays on a portion of the surface of the resin article. Also, by performing electroless plating on a resin article that has been modified in this way, a plating layer is formed on a portion of the surface of the resin article that has been modified. This step is referred to hereinafter as a plating step. With a method that includes the modifying step and the plating step, it is possible to manufacture a resin article having a plating layer. Below, these steps are described in detail with reference to FIG. 2, which shows a flowchart of treatment according to one embodiment, and FIGS. 6A to 6C, which illustrate treatment.

(Modifying Step)

In a modifying step (S210), ultraviolet rays are irradiated on a portion of the surface of a resin article. In this modifying step, ultraviolet rays are irradiated such that an interference pattern by at least two bundles of ultraviolet light is formed on the surface of the resin article. As a result of this step, a portion of the surface of the resin article is selectively modified such that electroless plating is deposited. For example, a portion of a resin article 110 shown in FIG. 6A is modified. As shown in FIG. 6B, a modified portion 160 is generated in the portion that was modified. As described later, in one embodiment, modification is performed using an ultraviolet ray laser, so by a laser beam ablation effect, a recess is formed in a laser beam irradiation portion of the resin article 110, and the modified portion 160 is formed in this recess.

FIG. 1 shows an example of the modifying step in the present embodiment. As shown in FIG. 1, ultraviolet rays are irradiated on the surface of the resin article 110 through a shielding member 120. The shielding member 120 has a transmitting portion that transmits ultraviolet rays such that ultraviolet rays are irradiated on a portion where a plating layer 170 is to be deposited by electroless plating. In one embodiment, the shielding member 120 is a plane-like member and includes an ultraviolet ray shielding portion 130 that shields from ultraviolet rays, and a UV-transmissive portion 140 that transmits ultraviolet rays. The specific configuration of the shielding member 120 is not particularly limited. For example, the shielding member 120 may be a quartz chrome mask, and in this case, the transmissive portion 140 is configured with quartz and the shielding portion 130 is a chrome film that has been formed on the transmissive portion 140.

In FIG. 1, the resin article 110 and the shielding member 120 are shown separated for the sake of description. However, the shielding member 120 may be in contact with the surface of the resin article 110, or the shielding member 120 may be disposed separated from the resin article 110 with a space or another holding member, for example. In this case, it is possible to dispose the resin article 110 and the shielding member 120 such that the surface of the resin article 110 to be modified and the surface of the shielding member 120 are parallel. As described later, the distance between the shielding portion 130 and the surface of the resin article 110 is controlled such that an appropriate irradiated region of ultraviolet rays is obtained.

In FIG. 1, an irradiated region 150 of ultraviolet rays is shown. As shown in the example in FIG. 1, ultraviolet rays having a linear irradiated region 150 are irradiated. Also, by movement of the resin article 110 and the shielding member 120, the surface of the resin article 110 is scanned by ultraviolet rays through the shielding member 120. As a result, ultraviolet rays are irradiated on the surface of the resin article 110 along the transmissive portion 140, and by an irradiated portion 155 being modified, the modified portion 160 is formed.

By condensing the ultraviolet rays from a ultraviolet ray lamp, an ultraviolet ray laser, or the like using a condenser lens (not shown), it is possible to irradiate the ultraviolet rays to the irradiated region 150. This sort of configuration is useful because, in comparison to a configuration in which light that has passed through a photomask is condensed with a condenser lens then irradiated on the surface of the resin article 110, the surface of the resin article 110 can more easily be modified according to a pattern having a large area. Also, the condensed ultraviolet rays having a linear irradiated region as shown in FIG. 1 have a comparatively high intensity, so this configuration is advantageous for modification efficiency. However, the irradiation method is not particularly limited, as long as ultraviolet rays are irradiated on the resin article through a shielding member.

In the present embodiment, the resin article 110 and the shielding member 120 are disposed such that an interference pattern by at least two bundles of ultraviolet light is formed on the surface of the resin article. The interference pattern can be formed, for example, using a slit, including a single slit and a plurality of slits, and a diffraction grating, including a transmissive diffraction grating and a reflective diffraction grating, and the like. In one example, ultraviolet rays are irradiated on a portion of the surface of the resin article 110 through the shielding member 120 provided with the transmissive portion 140. That is, the resin article 110 and the shielding member 120 are disposed such that an interference pattern by at least two bundles of ultraviolet light that were transmitted through the transmissive portion 140 is formed on the surface of the resin article 110. In one embodiment, the transmissive portion 140 is a single slit. That is, an interference stripe by a bundle of ultraviolet light that was transmitted through the vicinity of one end of the transmissive portion 140, and a bundle of ultraviolet light that was transmitted through the vicinity of the other end of the same transmissive portion 140, is formed on the surface of the resin article 110.

The interference pattern will be described with reference to FIG. 3. In FIG. 3, the surface of the resin article 110 is disposed parallel to the shielding member 120, and parallel ultraviolet rays 310 are incident on the shielding member 120 from the opposite side as the resin article 110. In this case, due to light diffraction at the slit, interference occurs between the bundles of ultraviolet light that passed through each position of the transmissive portion 140. Where the slit width is represented by d, the distance between the surface of the resin article 110 and the shielding member 120 is represented by l, and the wavelength of the ultraviolet rays is represented by λ, a bright line position and a dark line position Δx on the surface of the resin article 110 are known to be obtained as described below. The bright line position is a position where light bundles interfere constructively and the dark line position is a position where light bundles interfere destructively. Here, the distance l between the surface of the resin article 110 and the shielding member 120 is more specifically the distance between the surface of the resin article 110 and the shielding portion 130. For example, in a case where the shielding member 120 is a quartz mask having a plating layer, the distance l is the distance between the surface of the resin article 110 and the plating layer.

Δx=0,(m+0.5)·Δ·l/d

(bright line position)

Δx=m·λ·l/d

(dark line position)

In the above expressions, the bright line position and the dark line position Δx indicate the distance from a center point O, and the center point O is a point where ultraviolet rays transmitted through the center of the slit are incident on the surface of the resin article 110, when assuming that there is no diffraction. Also, m represents an integer of at least 1.

Thus, with ultraviolet rays it is possible to modify a region having a desired width on the surface of the resin article 110 by adjusting the slit width d, the distance l between the resin article 110 and the shielding member 120, and the wavelength λ of the ultraviolet rays. As a specific example, for example when the slit width d is set to 15 μm, the distance l between the surface of the resin article 110 and the shielding member 120 is set to 193 μm, and the wavelength λ of the ultraviolet rays is set to 193 nm, the dark line position Δx=2.48 μm (m=1). Because ultraviolet rays are not irradiated at the dark line position, the plating layer 170 is not deposited in the plating step described later. Accordingly, in this example, a fine plating layer 170 of 4.96 μm or less is formed at the position of the center point O by the plating step described later.

Thus, in one embodiment, the slit width (15 μm) is larger than the width (4.96 μm or less) of the portion of the surface of the resin article 110 to be modified such that electroless plating is deposited by ultraviolet rays that have been transmitted through the slit. According to such a configuration, when ultraviolet rays are irradiated in oxygen-containing atmosphere, a sufficient amount of ozone is generated in the vicinity of the slit having a large opening, so it is expected that modification of the surface of the resin article 110 is promoted. Compared to the slit width, the width of the plating layer 170 deposited as a result of the resin article being modified by the ultraviolet rays that were transmitted through the slit is 80% or less in one embodiment, is 50% or less in another embodiment, and is 35% or less in still another embodiment.

As described later, the plating layer 170 is deposited in the plating step described later if the amount of irradiation of ultraviolet rays is sufficiently large, but the plating layer 170 is not deposited in the plating step described later in a case where the amount of irradiation of ultraviolet rays is comparatively small. Accordingly, by adjusting the amount of irradiation of ultraviolet rays, it is possible to deposit the plating layer 170 at only one location or at a plurality of locations. For example, it is possible to deposit the plating layer 170 at only the position of the center point O, and it is possible to deposit the plating layer 170 at a total of three locations including the positions Δx=1.5λ·l/d in addition to the position of the center point O.

In another embodiment, an interference pattern is formed using a plurality of slits. FIG. 4 shows an example case of using two slits. In this case, due to light diffraction at the slits, interference occurs between a bundle of ultraviolet light that was transmitted through a slit 401, which is part of the transmissive portion, and a bundle of ultraviolet light that was transmitted through a slit 402, which is part of the transmissive portion. Where the distance between the slit 401 and the slit 402 is represented by d, a bright line position and a dark line position Δx of the surface of the resin article 110 are known to be obtained as described below.

Δx=0,m·λ·l/d

(bright line position)

Δx=(m−0.5)·λ·l/d

(dark line position)

Also, in still another embodiment, as shown in FIG. 5, an interference pattern is formed using a diffraction grating that has been provided in the shielding member 120. In this case, the diffraction grating acts as the transmissive portion 140. That is, interference occurs between a bundle of ultraviolet light that was transmitted through a first position of the diffraction grating, and a bundle of ultraviolet light that was transmitted through a second position of the diffraction grating. Where a grating constant of the diffraction grating is represented by d, a bright line position and a dark line position Δx of the surface of the resin article 110 are known to be obtained as described below.

Δx=0,m·λ·l/d

(bright line position)

Δx=(m−0.5)·λ·l/d

(dark line position)

As described above, different interference patterns are formed in a case where a single slit is used, a case where a plurality of slits are used, and a case where a diffraction grating is used. Specifically, by increasing the number of slits, it is possible to narrow the region where ultraviolet rays are irradiated. Thus, it is possible to select an appropriate slit configuration or diffraction grating according to the shape of the plating layer 170 intended to be formed.

As described above, by using a slit, it is possible to control the irradiated region of ultraviolet rays on the resin article 110. In one embodiment, the irradiated region on the surface of the resin article 110, of ultraviolet rays that have been transmitted through the slit, is striped. Also, in one embodiment, the shape of the transmissive portion 140 differs from the irradiated region on the resin article 110 of ultraviolet rays that have been transmitted through the transmissive portion 140. That is, the irradiated region on the resin article 110 of ultraviolet rays that have been transmitted through the transmissive portion 140 differs substantially from the irradiated region on the resin article 110 of ultraviolet rays that have been transmitted through the transmissive portion 140 in a case where it is assumed there is no diffraction. In one embodiment, the shape of the transmissive portion 140 is larger than the region on the resin article 110 to be modified such that the plating layer 170 is deposited by ultraviolet rays that have been transmitted through the transmissive portion 140.

According to the above sort of configuration, modification of the surface of the resin article 110 is performed while considering the action of light diffraction. Accordingly, it is conceivable that this configuration is less likely to be affected by a reduction in the amount of irradiation caused by diffraction of ultraviolet rays in a case of using a shielding member having a fine transmissive portion. Also, in an embodiment in which the shape of the transmissive portion 140 is larger than the irradiated region of ultraviolet rays that have been transmitted through the transmissive portion 140, the ultraviolet rays that have been transmitted through the transmissive portion 140 are condensed to the irradiated region on the resin article 110 by operation of the slit. Therefore, a greater amount of irradiation of ultraviolet rays on the resin article 110 occurs than in a case where ultraviolet rays are irradiated through a mask having a transmissive portion with the same size as the irradiated region. Therefore, it is conceivable that the surface of the resin article 110 can be more greatly modified than with a lesser amount of irradiation. On the other hand, also in an embodiment in which the shape of the transmissive portion 140 is smaller than the irradiated region of ultraviolet rays that have been transmitted through the transmissive portion 140, modification is performed while considering the action of light diffraction, so it is conceivable that a shift in the position of the irradiated region caused by diffraction of ultraviolet rays is suppressed.

The slit width can be appropriately selected according to the pattern of the plating layer 170 intended to be provided, if an interference pattern by diffraction of ultraviolet light occurs on the surface of the resin article 110. The slit width is 50 μm or less in one embodiment, and is 25 μm or less in still another embodiment. On the other hand, in order for the ultraviolet ray transmission amount to be sufficiently large, the slit width is at least 5 μm in one embodiment, and at least 10 μm in still another embodiment.

Thus, the shielding member 120 has a function of controlling an incidence position of transmitted ultraviolet rays on the resin article 110. Ultraviolet light bundles that have passed through the slits or the diffraction grating, due to interfering destructively or constructively, form a pattern of differing irradiation intensity on the resin article 110. Said another way, the shielding member 120 has a condensing portion that condenses transmitted ultraviolet rays. In one embodiment, a slit configured to be formed by the shielding portion 130 and the transmissive portion 140 acts as this condensing portion. Also, in another embodiment, a diffraction grating that acts as the transmissive portion 140 acts as this condensing portion. On the other hand, in another embodiment, the shielding member 120 may be provided with a lens such as a microlens that has been provided in the transmissive portion 140 as the condensing portion. In this case as well, an interference pattern does not occur on the resin article 110, but it is possible to suppress a reduction in the amount of ozone due to attenuation of the amount of irradiation due to diffraction, or due to the mask opening being small.

In one embodiment, irradiation of ultraviolet rays is performed in an atmosphere that includes at least one of oxygen and ozone. As a specific example, irradiation of an ultraviolet ray laser beam on a resin article can be performed in air. In another embodiment, in order to further promote modification, irradiation is performed in an atmosphere that includes ozone.

When ultraviolet rays are irradiated, oxygen in the atmosphere is decomposed, generating ozone. Further, active oxygen is generated in the course of ozone decomposing. Even if the resin article 110 and the shielding member 120 were in contact, a small amount of oxygen exists between the resin article 110 and the shielding member 120, so ozone is generated in the vicinity of the resin article 110. Also, at the surface of the resin article 110, bonds in the molecules that constitute the resin article 110 are broken. At this time, molecules that constitute the resin article 110 react with active oxygen, and the surface of the resin article 110 oxidizes, that is, at the surface of the resin article 110, bonds such as C—O bonds, C═O bonds, and C(═O)—O bonds (carboxyl group skeletal structure portion) are formed. Such a hydrophilic group increases the chemical adsorption of the resin article 110 and the plating layer 170. Also, since a portion made brittle by oxidation of the surface of the resin article 110 will come off in a later step such as an alkali treatment step for example, a fine rough surface is formed in a portion where ultraviolet rays have been irradiated. Because of this rough surface, physical adsorption of the resin article 110 and the plating layer 170 increases due to an anchoring effect. Further, in a portion that has been modified, it is possible to selectively cause adsorption of catalyst ions when performing electroless plating.

Energy of photons of a specific wavelength is expressed by the following formulas.

E=Nhc/λ(KJ·mol ⁻¹)

N=6.022×10²³ mol ⁻¹

(Avogadro's constant)

h=6.626×10⁻³⁷ KJ·s

(Plank's constant)

c=2.988×10⁸ m·s ⁻¹

(speed of light)

λ=light wavelength (nm)

Here, the bond energy of oxygen molecules is 490.4 KJ·mol⁻¹. From the photon energy formula, this bond energy is about 243 nm when converted to light wavelength. This indicates that oxygen molecules in the atmosphere will absorb ultraviolet rays with a wavelength of 243 nm or less and decompose. Thus, ozone O₃ is generated. Further, active oxygen is generated in the course of ozone decomposing. At this time, when there are ultraviolet rays with a wavelength of 310 nm or less, ozone is efficiently decomposed, and active oxygen is generated. Further, ultraviolet rays with a wavelength of 254 nm decompose ozone most efficiently.

O₂ +hν(243 nm or less)→O(3P)+O(3P)

O₂+O(3P)→O₃(ozone)

O₃ +hν(310 nm or less)→O₂+O(1D)(active oxygen)

-   -   O(3P): ground state oxygen atom     -   O(1D): excited oxygen atom (active oxygen)

On the other hand, in another embodiment, irradiation of ultraviolet rays on the resin article 110 can be performed in another gas atmosphere, for example, such as an amine compound gas atmosphere like ammonia or an amide compound gas atmosphere. By performing irradiation in an amine compound gas atmosphere or an amide compound gas atmosphere, it is possible to oxidize the surface of the resin article 110, that is, possible to generate bonds including nitrogen atoms at the surface of the resin article 110. That is, the surface of the resin article 110 is modified so as to include nitrogen atoms, so adsorption with the plating layer improves, so it is possible to perform selective plating in an irradiated portion. In a case where modification is performed by ultraviolet rays after isolating the item to be processed from an atmosphere at normal pressure, and then changing pressure or enveloping in compound gas, it is possible to suitably select a wavelength appropriate for the reaction. On the other hand, irradiating ultraviolet rays having a wavelength of 243 nm or less in air including oxygen is advantageous because modification can be performed with low cost.

Also, it is not necessary to perform irradiation of ultraviolet rays on the resin article 110 in an air atmosphere. For example, by irradiating ultraviolet rays with a wavelength that causes a chemical change of the resin article 110, it is possible to modify the surface of the resin article 110 even in a vacuum.

When modifying the surface of the resin article 110 using an interference pattern, it is possible to irradiate coherent ultraviolet rays such that interference occurs easily. Coherent ultraviolet rays can be irradiated using an ultraviolet ray laser, for example.

As an ultraviolet ray laser, it is possible to use an excimer laser, which is one type of gas laser. In an excimer laser, an excited state is produced by momentarily applying a high voltage to a gas mixture of inactive gas and halogen gas, and high output pulse oscillation is performed.

The laser beam wavelength changes depending on the combination of the inactive gas and the halogen gas used to generate the excimer laser beam. The relationship between the gas combination and the laser beam wavelength is shown below.

F₂ excimer laser: wavelength 157 nm

ArF excimer laser: wavelength 193 nm

KrCl excimer laser: wavelength 222 nm

KrF excimer laser: wavelength 248 nm

In one embodiment, an ArF excimer laser is used as the ultraviolet ray laser. An ArF excimer laser has a comparatively short wavelength, so modification is performed more efficiently. Also, compared to an F₂ excimer laser, an ArF excimer laser has less absorption by oxygen in air and therefore is easier to manage.

A KrCl excimer laser or a KrF excimer laser may also be used as the ultraviolet ray laser. These lasers have less absorption by oxygen in air than an ArF excimer laser and therefore are easier to manage.

A laser beam from an excimer laser can have a shape reflecting the shape of a discharge region, for example a rectangular beam shape of about 20×10 mm. Because the laser beam from an excimer laser is thick and has high pulse energy, in a case of using an excimer laser, it is possible to treat a comparatively large area at one time with a comparatively high irradiation intensity. Also, by using an appropriate lens, the laser beam can be modified to a linear shape, as shown in FIG. 1.

On the other hand, there are cases where plating is not deposited in a portion where ultraviolet rays were irradiated by merely irradiating ultraviolet rays having a high energy density, such as with an ultraviolet ray laser, on the surface of the resin article 110. The surface of the resin article 110 is modified by irradiating an ultraviolet ray laser beam, but the modified layer is eliminated due to the ablation effect by an ultraviolet laser beam. Therefore, it is possible that at least a fixed amount of modification will not be obtained, and so an amount of modification sufficient for plating to be deposited cannot be performed. Ablation is a phenomenon where the surface of material is removed by evaporation.

Consequently, in one embodiment, after irradiating an ultraviolet ray laser beam on the surface of the resin article 110, further modifying treatment is performed. This modifying treatment may be selectively performed on a portion of the resin article 110, for example, a portion where the plating layer 170 is intended to be deposited. However, this modifying treatment may also be performed on a larger region that encompasses the portion where the plating layer 170 is intended to be deposited, and for example may also be performed on the entire resin article 110. In this case, the modifying treatment is performed such that the plating layer 170 will not be deposited in a portion where the plating layer 170 is not to be deposited. In a portion where the laser beam is being intensely irradiated, modification is already progressing, so modification such that the plating layer 170 will be deposited is possible even with weak modifying treatment. On the other hand, in a portion where the laser beam has not been irradiated or has only been irradiated weakly, modification has not progressed much, so the plating layer 170 will not be deposited with weak modifying treatment. Accordingly, even in a case where modifying treatment is performed uniformly on the entire resin article 110, in the plating step described later, it is possible to selectively cause the plating layer 170 to be deposited in a desired portion where the laser beam is being intensely irradiated.

As the modifying treatment, it is possible to use a plasma treatment, an acid treatment, an alkali treatment, or the like, and in the present embodiment, an ultraviolet ray irradiation treatment is used. For example, the surface of the resin article 110 is further modified by irradiating ultraviolet rays using an ultraviolet ray lamp or an ultraviolet ray LED or the like that continuously radiates ultraviolet rays. Irradiation of ultraviolet rays can be performed in a similar atmosphere as irradiation by an ultraviolet ray laser beam, described above. For example, ultraviolet rays can be irradiated in an atmosphere including at least one of oxygen and ozone. In order to improve modification efficiency, in one embodiment, ultraviolet rays having a wavelength of 243 nm or less are irradiated.

Examples of an ultraviolet ray lamp include a low pressure mercury lamp, an excimer lamp, and the like. A low pressure mercury lamp can irradiate ultraviolet rays having a wavelength of 185 nm and 254 nm. Also, for reference, an example of an excimer lamp that can be used in air is given below. An Xe₂ excimer lamp is commonly used as an excimer lamp.

Xe₂ excimer lamp: wavelength 172 nm

KrBr excimer lamp: wavelength 206 nm

KrCl excimer lamp: wavelength 222 nm

When irradiating ultraviolet rays on the resin article 110, irradiation of ultraviolet rays is controlled such that the irradiation amount becomes a desired value. The irradiation amount can be controlled by changing the irradiation time. Also, the irradiation amount can be controlled by changing the output, lamp quantity, irradiation distance, or the like of the ultraviolet ray lamp.

In one embodiment, energy density is at least 1.0×10⁵ W/cm² for the primary wavelength of the ultraviolet ray laser beam irradiated on the resin article 110. The upper limit of energy density is not particularly limited, and for example, can be 1.0×10¹⁵ W/cm² or less. In the present specification, unless specifically stated otherwise, the irradiation amount and irradiation intensity of ultraviolet rays refer to values for the primary wavelength. In the present specification the primary wavelength refers to a wavelength having the highest intensity in a region of 243 nm or less. Specifically, in the case of a low pressure mercury lamp the primary wavelength is 185 nm. When a single wavelength laser is used as the ultraviolet ray laser, the wavelength of the laser beam is the primary wavelength.

In one embodiment, the ultraviolet ray laser beam is irradiated in pulses. By irradiating the laser beam in pulses for a short time, it is possible to avoid an increase in the temperature of the resin article 110 and the shielding member 120. Therefore, it is possible to suppress shifting of the position of the modified portion caused by differences in the thermal expansion coefficient between the resin article 110 and the shielding member 120. In one embodiment, the pulse width is at least 10 ns and not more than 100 ns.

The irradiation amount and the number of pulses of the laser beam can be appropriately selected according to the type or the like of the resin article 110. In one embodiment, a laser beam having an energy density per pulse of at least 50 mJ/cm² and not more than 5000 mJ/cm² is irradiated. Also, in one embodiment, a laser beam is irradiated such that a total irradiation amount is at least 100 mJ/cm² and not more than 50,000 mJ/cm².

The irradiation amount of ultraviolet rays when performing further modification after the ultraviolet ray laser beam was irradiated can be appropriately adjusted such that the plating layer 170 is selectively deposited in a desired portion where the laser beam is being intensely irradiated. In one embodiment, the total irradiation amount of ultraviolet rays for the primary wavelength is not more than 400 mJ/cm². Also, in one embodiment, the total irradiation amount of ultraviolet rays for the primary wavelength is at least 50 mJ/cm².

However, the plating deposit conditions are variable depending on the type of plating solution, the type of the resin article 110, the degree of contamination of the surface of the resin article 110, the concentration, temperature, pH, and age-related degradation of the plating solution, fluctuation in output of the ultraviolet ray lamp, focus shift of the ultraviolet ray laser, and the like. In this case, the irradiation amount from the ultraviolet ray laser, the ultraviolet ray lamp, and the like is appropriately determined with reference to the numerical values stated above, such that plating is selectively deposited in a desired portion. The irradiation amount can be controlled by changing the output, lamp quantity, irradiation distance, or the like of the ultraviolet ray lamp.

According to the investigations by the inventors of the present application, the ease of depositing the plating layer 170 in the plating step depends on an oxygen atom existence ratio at the surface of the resin article 110. It is conceivable that the oxygen atom existence ratio increases as modification by ultraviolet rays or the like proceeds. In one embodiment, the irradiation amount of the ultraviolet ray laser beam is adjusted such that in a portion where the plating layer 170 is to be deposited, after irradiating the ultraviolet ray laser beam, the oxygen atom existence ratio of the surface of the resin article 110 is at least 3.0%, or at least 3.8%. Also, the irradiation amount of the ultraviolet rays is adjusted such that in a portion where the plating layer 170 is to be deposited, after performing further modification, the oxygen atom existence ratio is at least 18%, or at least 20.1%. There is not an upper limit to the oxygen atom existence ratio, and the oxygen atom existence ratio is not particularly limited as long as plating is deposited. On the other hand, the irradiation amount of the ultraviolet rays is adjusted such that in a portion where the plating layer 170 is not to be deposited, after performing further modification, the oxygen atom existence ratio is no more than 15%, or no more than 12.6%. There is not a lower limit to the oxygen atom existence ratio, and the oxygen atom existence ratio is not particularly limited as long as plating is not deposited.

In the present specification, the oxygen atom existence ratio refers to an existence ratio (atom %) of oxygen atoms relative to all atoms at the surface of the resin article 110, which has been calculated by XPS measurement. However, because it is conceivable that hydrophilicity of the surface of the resin article 110 is greatly affected by the ratio of carbon atoms and oxygen atoms, and because hydrogen atoms cannot be detected by XPS measurement, the number of hydrogen atoms is not included in calculations. Here, also, there are cases where the oxygen atom existence ratio changes somewhat due to measurement conditions, detection error of each apparatus, or the like.

The resin article 110 used in the present embodiment is not particularly limited, as long as the resin article 110 has a resin material on the surface that can be modified by ultraviolet rays. Examples of the resin material include a polyolefin including cyclopolyolefin, i.e., a cyclo-olefin polymer or a polyolefin such as polystyrene, a polyester such as polyethylene terephthalate, a polyvinyl such as polyvinyl chloride, a polycarbonate, a polyimide, or the like.

The shape of the resin article 110 also is not particularly limited. For example, the resin article 110 may have a film-like shape or may have a plate-like shape. Further, the thickness of the resin article 110 also is not particularly limited. Also, it is not necessary to configure the resin article 110 with only resin. That is, in one embodiment, the resin article 110 is a composite material article having a coated structure obtained by coating the surface of another material article with resin material. As a specific example of a composite material article, there is a composite material article in which the surface of a metal material article has been coated with a resin material.

In one embodiment, the resin article 110 has a smooth surface. Due to the resin article 110 having a smoother surface, a more uniform plating layer 170 is formed by plating. By using such a smooth plating layer 170 as conductive wiring, it is possible to suppress high frequency signal loss. In the present specification, arithmetic mean roughness Ra is defined by JIS B0601: 2001. According to a method for modifying the surface of the resin article 110 using ultraviolet rays as in the present embodiment, nanometer-order fine unevenness is formed in the surface of the resin article 110. In one embodiment, arithmetic mean roughness Ra of the resin article surface is 10 nm or less. Unevenness formed in this way is expected to be remarkably small compared to micrometer-order unevenness that, for example, is obtained by irradiating a high-intensity visible laser beam on the surface of a resin article, or is formed by treatment with chromic acid or the like.

(Plating Step)

In a plating step (S220), as shown in FIG. 6C, the plating layer 170 is formed on the surface of the resin article 110 whose surface has been modified in the modifying step. Thus, a resin article 190 having a plating layer is manufactured. In the modifying step, selective modification has been performed such that the plating layer 170 is deposited in a desired modified portion 160. Accordingly, even in a case where, for example, the entire resin article 110 has been immersed in a plating solution, the plating layer 170 is selectively deposited in a desired modified portion 160. Also, plating is not deposited in a portion adjacent to the desired portion. Accordingly, it is not necessary to perform patterning on the plating layer by a method such as photolithography and etching after forming the plating layer 170.

In one embodiment, the plating layer 170 is formed by an electroless plating method. The specific electroless plating method is not particularly limited. Examples of electroless plating methods that can be adopted include an electroless plating method employing a formalin-containing electroless plating bath, and an electroless plating method in which hypophosphorous acid is used as a reducing agent, which leads to a slow deposit speed but is easily managed. As more specific examples of the electroless plating method, there are electroless nickel plating, electroless copper plating, electroless copper-nickel plating, electroless zinc oxide plating, and the like. The plating layer 170 to be formed, in one embodiment, is a metal film, and may also be a ceramic film such as a zinc oxide plating layer. By modifying the resin article 110 as described above, adhesion of the modified portion 160 and the deposited plating layer improves.

In one embodiment, the electroless plating can be performed by the below method.

1. (Alkali Treatment) The resin article 110 is immersed in an alkali solution and oil is removed to improve hydrophilicity. Examples of the alkali solution include a sodium hydroxide aqueous solution or the like.

2. (Conditioner Treatment) The resin article 110 is immersed in a solution containing a binder of the resin article 110 and catalyst ions. Examples of the binder include a cationic polymer or the like.

3. (Activator Treatment) The resin article 110 is immersed in a solution including catalyst ions. Examples of catalyst ions include a palladium complex such as hydrochloric acid palladium complex, or the like.

4. (Accelerator Treatment) The resin article 110 is immersed in a solution containing a reducing agent, causing reduction and depositing of catalyst ions. Examples of the reducing agent include hydrogen gas, dimethylamine borane, sodium borohydride, and the like.

5. (Electroless Plating Treatment) The plating layer 170 is deposited on the deposited catalyst.

Electroless plating according to this sort of method can be performed using, for example, an electroless plating solution set, such as a Cu—Ni plating solution set “AISL” made by JCU Co.

In another embodiment, as catalyst ions, a palladium complex is used that easily adheres to the modified portion 160 and at least partially has a positive charge. In order to improve adhesion to the modified portion 160, in one embodiment, a solution is used that includes palladium complex ions having a positive charge in the solution. An example of a palladium complex that at least partially has a positive charge is a complex in which amine ligands are in coordination bonds. Also, another example of a palladium complex that at least partially has a positive charge is a palladium basic amino acid complex.

In this case, by immersing the resin article 110 in a binder solution, it is not necessary to increase the affinity of the resin article 110 and catalyst ions. A palladium basic amino acid complex is a complex of palladium ions and a basic amino acid. The palladium ions are not limited, but divalent palladium ions are often used. The basic amino acid may be a natural amino acid or an artificial amino acid. In one embodiment, the amino acid is an α-amino acid. Basic amino acids include amino acids having a basic substituted group such as an amino group or a guanidyl group or the like in a side chain. Examples of a basic amino acid include lysine, arginine, ornithine, or the like.

As the catalyst ions, it is advantageous for ease of selectively depositing the plating layer 170 to use a palladium complex at least partially having a positive charge. That is, when using this sort of catalyst, it is more difficult to deposit the plating layer 170 in a portion where the plating layer 170 is not to be provided, that is, in a portion that has not been sufficiently modified in the modifying step.

A specific example of a palladium basic amino acid complex is expressed by below Formula (I).

In above Formula (I), L₁ and L₂ each independently represent an alkylene group having a carbon number of at least 1 and not more than 10, and R₃ and R₄ each independently represent an amino group or a guanidyl group. Examples of an alkylene group having a carbon number of at least 1 and not more than 10 include straight-chain alkylene groups such as a methylene group, 1,2-ethanediyl group, 1,3-propanediyl group, n-butane-1,4-diyl group, or the like. In above Formula (I), two amino groups are coordinated in trans position, but two amino groups may also be coordinated in cis position. Also, the palladium basic amino acid complex may have a mixture of groups in cis position and trans position.

In another embodiment, the plating layer 170 can be formed by a high speed electroless plating method. According to a high speed electroless plating method, it is possible to form a thicker plating layer. In still another embodiment, on the plating layer 170 that has been formed by electroless plating, it is possible to deposit plating by additionally using electroplating. According to this method, it is possible to form a still thicker plating layer 170. The specific method of electroplating is not particularly limited.

There is no special limitation on the thickness of the plating layer 170 to be obtained. A plating layer 170 of an appropriate thickness is formed according to the application of the resin article 190 having a plating layer to be obtained. Also, there is no special limitation on the material of the plating layer 170. An appropriate material is selected according to the application of the resin article 190 having a plating layer to be obtained.

The resin article 190 having a plating layer that has been obtained in this way can be used in various applications. Specifically, according to the present embodiment, it is possible to easily manufacture a resin article having fine wiring. Such a resin article having fine wiring can be used as a circuit board, for example. By adopting finer wiring, it is possible to increase wiring density and reduce the size of the circuit board, so electronic devices having the circuit board can be made smaller. Also, as one example, a resin article having fine wiring arranged in a mesh-like manner on its surface can be used as a conductive film, for example. Specifically, in a transparent conductive film where wiring has been provided on a transparent resin article, by adopting finer wiring, it is possible to improve visibility through the transparent conductive film.

EXAMPLES Experiment 1 (Substrate Treatment)

In Experiment 1, a cyclo-olefin polymer material (made by Zeon Corp., ZeonorFilm ZF-16, thickness 100 μm), which is a resin material, was used as the substrate for electroless plating.

First, before performing surface modification, the below treatment was performed to clean the substrate surface.

1. Ultrasonic cleaning for 3 minutes in pure water at 50° C. 2. Immersion for 3 minutes in alkali cleaning solution (containing 3.7% sodium hydroxide) at 50° C. 3. Ultrasonic cleaning for 3 minutes in pure water at 50° C.

4. Drying

(Modifying Step)

Next, an ultraviolet ray laser beam was irradiated on a desired portion of the substrate. Details of the ultraviolet ray laser used in Experiment 1 are given below.

Ultraviolet ray laser: ArF excimer laser (primary wavelength 193 nm)

Ultraviolet ray laser irradiation device: LPXpro305 made by Coherent Co.

Irradiation conditions: frequency 50 Hz, pulse width 25 ns, 200 pulses

Energy density at the irradiated surface per pulse: 100 mJ/cm²

The oxygen atom existence ratio for the substrate irradiated by the ultraviolet ray laser beam in this way was measured to be 8.8% by XPS measurement. Here, the XPS measurement apparatus is unable to measure hydrogen atoms. Therefore, the existence ratio of atoms at the surface of the cyclo-olefin polymer material in Experiment 1 was calculated based on only carbon atoms and oxygen atoms.

Also, after irradiating the ArF excimer laser beam for 200 pulses on the cyclo-olefin polymer material, the shape of the substrate surface was checked using an SEM (scanning electron microscope), and the results of this check showed that a recess was formed in the laser beam irradiated portion, with a depth of about 0.2 μm. Also, it was possible to adjust the depth by increasing or decreasing the number of laser beam pulses.

Next, further modification was performed by irradiating an ultraviolet ray lamp on a desired portion of the substrate after laser beam irradiation. Details of the ultraviolet ray lamp (low pressure mercury lamp) used in Experiment 1 are given below.

Low pressure mercury lamp: UV-300 made by Samco Corp. (primary wavelengths 185 nm, 254 nm)

Illuminance at irradiation distance 3.5 cm:

-   -   5.40 mW/cm² (254 nm)     -   1.35 mW/cm² (185 nm)

Specifically, on the substrate after irradiating the ArF excimer laser beam for 200 pulses on the cyclo-olefin polymer material, further using the above ultraviolet ray lamp, ultraviolet rays of 1.35 mW/cm² (185 nm) were irradiated for 1 minute at a distance of 3.5 cm from the ultraviolet ray lamp. In this case, the total amount of exposure was 1.35 mW/cm²×60 seconds=81 mJ/cm².

The status of surface modification for the substrate irradiated with ultraviolet rays in this way was analyzed by XPS measurement. For a portion on the substrate that was irradiated by the laser beam, the oxygen atom existence ratio after performing irradiation by the ultraviolet ray lamp was 20.1%. Also, for a portion on the substrate that was not irradiated by the laser beam, the oxygen atom existence ratio after performing irradiation by the ultraviolet ray lamp was 12.6%. Thus, in Experiment 1, the oxygen atom existence ratio of a portion on the substrate that was not irradiated by the laser beam was suppressed to no more than 15%. Therefore, as described later, it was possible to selectively deposit plating in a portion where the laser beam was irradiated.

(Plating Step)

Next, the plating step in which electroless plating is performed was performed on the substrate that was irradiated with ultraviolet rays in the modifying step. A Cu—Ni plating solution set “AISL” made by JCU Co. was used as an electroless plating solution. Specific treatment in the plating step is shown in Table 1.

TABLE 1 Treatment Step Conditions Remarks Alkali treatment 50° C., 2 min. Oil removal, wettability improved Water rinse + dry (air blow) Conditioner step 50° C., 2 min. Binder of catalyst ions and substrate provided Warm water rinse + water rinse + dry (air blow) Activator 50° C., 2 min. Catalyst ions provided Water rinse + dry (air blow) Accelerator 40° C., 2 min. Catalyst ions reduction, conversion to metal Water rinse + dry (air blow) Electroless Cu—Ni 60° C., 5 min. Electroless plating plating deposited Water rinse + dry (air blow)

When electroless plating according to the steps shown in Table 1 was finished, a plating layer by electroless plating had been formed only at a location where the laser beam was irradiated.

Experiment 2

Except for changing the number of times of irradiating the laser beam in the irradiating step, the same modifying step and plating step as in Experiment 1 were performed, and it was observed whether or not a plating layer was formed at a location where the laser beam was irradiated. The results are shown in Table 2. In Table 2, ‘YES’ indicates that plating was deposited, and ‘NO’ indicates that plating was not deposited.

TABLE 2 Ultraviolet ray irradiation amount Oxygen atom existence ratio in further modifying treatment after laser beam irradiation 81 mJ/cm² (1 min. irradiation) 0.0% NO 3.8% NO 4.2% NO 7.1% YES 8.8% YES

As shown in Table 2, when ultraviolet rays of 81 mJ/cm² are irradiated in further modifying treatment, by adjusting the oxygen atom existence ratio of a laser beam-irradiated portion to be equal to or more than 6.5%, plating will be deposited in the laser beam-irradiated portion. Specifically, in Experiment 2, in which an ArF excimer laser beam with an energy density of 100 mJ/cm² is irradiated, when the number of pulses is at least 20, the oxygen atom existence ratio is at least 6.5%. It is conceivable that the oxygen atom existence ratio will not decrease even if the number of pulses is increased, so it is conceivable that there is no particular upper limit for the number of pulses, for a case where the number of pulses is 200 or less, it was confirmed that the oxygen atom existence ratio is at least 6.5%.

Experiment 3

Except for changing the number of times of irradiating the laser beam in the modifying step, and irradiating ultraviolet rays for 3 minutes in the further modifying treatment, the same modifying step and plating step as in Experiment 1 were performed, and it was observed whether or not a plating layer was formed at a location where the laser beam was irradiated. The results are shown in Table 3. In Table 3, ‘YES’ indicates that plating was deposited, and ‘NO’ indicates that plating was not deposited.

TABLE 3 Ultraviolet ray irradiation amount Oxygen atom existence ratio in further modifying treatment after laser beam irradiation 243 mJ/cm² (3 min. irradiation) 0.0% NO 3.8% YES 4.2% YES 7.1% YES 8.8% YES

As shown in Table 3, when ultraviolet rays of 243 mJ/cm² are irradiated in further modifying treatment, the oxygen atom existence ratio of a laser beam-irradiated portion is at least 3.0%, so it is clear that plating will be deposited in the laser beam-irradiated portion.

Example 1

A cyclo-olefin polymer material (made by Zeon Corp., ZeonorFilm ZF-16, thickness 100 μm), which is a resin material, was used as the substrate.

First, before performing surface modification, the below treatment was performed to clean the substrate surface.

1. Ultrasonic cleaning for 3 minutes in pure water at 50° C. 2. Immersion for 3 minutes in alkali cleaning solution (containing 3.7% sodium hydroxide) at 50° C. 3. Ultrasonic cleaning for 3 minutes in pure water at 50° C.

4. Drying

Next, in air, an ultraviolet ray laser beam was irradiated on the substrate through a quartz chrome mask placed on the substrate. Details of the ultraviolet ray laser used in this example are given below.

Ultraviolet ray laser: ArF excimer laser (primary wavelength 193 nm)

Ultraviolet ray laser irradiation device: LPXpro305 made by Coherent Co.

Irradiation conditions: frequency 50 Hz, pulse width 25 ns, 40 pulses

Energy density at the irradiated surface per pulse: 100 mJ/cm²

From the ultraviolet ray laser irradiation device, with an optical system, a 4.5 cm×1.5 mm plane-like ultraviolet ray laser beam was irradiated on the quartz chrome mask. As shown in FIG. 1, by scanning on the quartz chrome mask with this ultraviolet ray laser beam, modification of the substrate surface was performed. The scanning was performed such that 40 pulses of the laser beam were irradiated at each location on the quartz chrome mask.

Also, as shown in FIG. 1, the quartz chrome mask had a slit perpendicular to the longitudinal direction of the irradiated region of the ultraviolet ray laser beam. The slit width was 15 μm. Further, a distance between a chrome film of the quartz chrome mask and the surface of the resin article was 194 μm.

Next, in air, ultraviolet rays from an ultraviolet ray lamp were irradiated on the entire surface of the resin article after the ultraviolet ray laser beam was irradiated. Details of the ultraviolet ray lamp (low pressure mercury lamp) used in this example are given below.

Low pressure mercury lamp: UV-300 made by Samco Corp. (primary wavelengths 185 nm, 254 nm)

Irradiation distance: 3.5 cm

Irradiation time: 2 min. 30 sec.

Illuminance at irradiation distance 3.5 cm:

-   -   5.40 mW/cm² (254 nm)     -   1.35 mW/cm² (185 nm)

(Plating Step)

Next, the plating step in which electroless plating is performed was performed on the substrate that was irradiated with ultraviolet rays in the modifying step. Specifically, first, alkali treatment was performed on the substrate. That is, an alkali treatment solution used in a Cu—Ni plating solution set “AISL” made by JCU Co. was heated to 50° C., and the substrate was immersed for three minutes. Afterward, the substrate was rinsed with pure water.

Next, a catalyst ion providing treatment was performed on the substrate. Specifically, an activator solution (made by JCU Co., product name ELFSEED ES-300) containing a palladium (II) basic amino acid complex was heated to 50° C., and the substrate was immersed for five minutes. Afterward, the substrate was rinsed in pure water.

Next, a reducing treatment was performed on the substrate. Specifically, an accelerator solution (made by JCU Co., product name ELFSEED ES-400) was heated to 40° C., and the substrate was immersed for four minutes. Afterward, the substrate was rinsed in pure water.

Next, electroless copper-nickel plating was performed on the substrate. Specifically, an electroless Cu—Ni plating solution used in a Cu—Ni plating solution set “AISL” made by JCU Co. was heated to 60° C., and the substrate was immersed for five minutes. Afterward, the substrate was rinsed in pure water, and dried. Thus, a resin article having a plating layer was manufactured.

When the obtained resin article having a plating layer was observed, as shown in FIG. 7, three band-like plating layers were observed to be striped corresponding to the ultraviolet rays that were transmitted through one slit. The widths of the respective plating layers were 3.0 μm, 5.0 μm, and 3.0 μm. The respective plating layers were separated well, and disconnections were not seen.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2014-255413, filed Dec. 17, 2014, which is hereby incorporated by reference herein in its entirety. 

What is claimed is:
 1. A modification method comprising: irradiating ultraviolet rays on part of a surface of a resin article, so as to selectively modify the part of the surface of the resin article such that an electroless plating layer will be deposited, wherein the ultraviolet rays are irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article.
 2. The modification method according to claim 1, wherein in the irradiating, the ultraviolet rays are irradiated on the part of the surface of the resin article through a shielding member having a UV-transmissive portion, and the interference pattern is formed by ultraviolet rays which come through the UV-transmissive portion.
 3. A modification method comprising: irradiating ultraviolet rays on part of a surface of a resin article through a shielding member having a UV-transmissive portion so as to selectively modify the part of the surface of the resin article such that an electroless plating layer is deposited, wherein the shielding member condenses ultraviolet rays which go through the shielding member.
 4. The modification method according to claim 2, wherein the UV-transmissive portion is a slit.
 5. The modification method according to claim 4, wherein the width of the slit is larger than the width of the part of the surface of the resin article to be modified such that an electroless plating layer is deposited.
 6. The modification method according to claim 4, wherein an region on the surface of the resin article irradiated by ultraviolet rays which come through the slit has a striped pattern.
 7. The modification method according to claim 2, wherein the UV-transmissive portion is a diffraction grating.
 8. The modification method according to claim 2, wherein the ultraviolet rays are irradiated on the surface of the resin article by scanning the surface of the resin article with ultraviolet rays having a linear irradiation area through the shielding member.
 9. The modification method according to claim 1, wherein irradiation of the ultraviolet rays is performed in an atmosphere that contains at least one of oxygen or ozone.
 10. The modification method according to claim 1, wherein the ultraviolet rays are an ultraviolet ray laser beam having a wavelength of 243 nm or less.
 11. The modification method according to claim 10, wherein in the irradiating, after irradiating the ultraviolet ray laser beam, a further modifying treatment is performed on a region encompassing the part of the surface of the resin article.
 12. The modification method according to claim 11, wherein the further modifying treatment is to irradiate ultraviolet rays having a wavelength of 243 nm or less on a region encompassing the part of the surface of the resin article using an ultraviolet ray lamp or an ultraviolet ray LED, in an atmosphere that contains at least one of oxygen or ozone.
 13. The modification method according to claim 1, wherein the surface of the resin article includes at least one of polyolefin, polyester, polyvinyl, polycarbonate, or polyimide.
 14. A method for manufacturing a resin article having a plating layer, the method comprising: selectively modifying part of a surface of a resin article by irradiating ultraviolet rays on the part of the surface of the resin article, the ultraviolet rays being irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article; and forming a plating layer on the part of the surface of the resin article by electroless plating.
 15. A resin article having a plating layer that was manufactured according to a method comprising: selectively modifying part of a surface of a resin article by irradiating ultraviolet rays on the part of the surface of the resin article, the ultraviolet rays being irradiated such that an interference pattern by the ultraviolet rays is formed on the surface of the resin article; and forming a plating layer on the part of the surface of the resin article by electroless plating. 